The off-road environment can be brutal on drivetrain parts, especially axles, but the engine is often seen as secondary—as long as it runs okay and makes enough power to climb your favorite hill, it’s good enough. Right? But what’s the fun in “good enough”? The key to a good engine in an off-road situation is torque, and as much of it as possible.
Horsepower numbers are secondary unless you plan on blasting across Baja at high speeds all day. Torque is what will move your truck over obstacles and up hills. If your truck’s engine doesn’t have enough grunt, or it’s simply worn out, now’s the time to replace it with a torquey crate motor.
The classic third-gen GM C/K pickups, vintage 1973 to 1987 (a 1980 Chevy 4×4 pictured), are ripe for engine swaps.
So where do you find the right crate motor for your truck? Today’s automotive aftermarket is rife with all kinds of crate engines. From the OEs to the various engine builders, you can find nearly any kind of ready-to-drop-in engine you want, from stock replacement to fire-breathing monster and everything in between.
This is especially true for GM pickups, so for this story we focused on crate engines for the most popular GM pickups and SUVs–the 1973 to 2013 model-year full-size pickups and SUVs from Chevy and GMC. This encompasses the four most popular generations of light trucks from The General.
A new 350 ci V8 (Universal Crate Engine) from Pace is a great entry-level direct replacement for the 1973 to 1987 GM trucks.
We broke the crate motor recommendations down into direct replacement, high-performance replacement, and late model retrofit LS series replacement for each of the four generations of GM trucks since 1973. Keep in mind that since emissions regulations are different in all parts of the country, unless otherwise stated here, you’re on your own with that.
The following recommendations are not ours though. They come straight from the experts at Chevrolet Performance, Pace Performance, and Scoggin-Dickey Performance Center (SDPC). We went to these three companies for recommendations because GM is the OE and has a vibrant crate motor inventory, and Pace and SDPC are two of the largest volume performance engine retailers in the USA. Here’s what the experts had to say.
1973-1987 CHEVY/GMC C/K TRUCKS
The 1973 Chevy/GMC pickups were clean-sheet designs that came out mid-way through 1972, replacing what many consider the last of the “classic” GM light trucks, those made from 1967 to 1972. Considered the third-generation, these completely redesigned new trucks had a squared-off look.
The GM HT383 Crate Engine from Pace is a small package tuned for big torque, and a good hi-po replacement for third-gen C/K trucks.
They were unfortunately born in the early days of emissions and mileage concerns that choked the life out of nearly every engine of the day. The 400 ci small-block was strangled to only 185 hp for ’75, and then in 1978, the great-idea-with-poor-execution Olds diesel V8 became an option. All this means that these C/Ks are perfect for an engine swap.
Pace Performance: New Chevy 350 CID V8 – Universal Crate Engine, part no. 10067353. Chuck Fitch of Pace said, “This engine remains our most popular crate engine of all time. This is a great entry-level replacement engine for older trucks. All of the parts in this engine, including the block, are brand new.”
It has an iron block and heads with an 87-octane-friendly 8.5:1 compression ratio, a two-piece rear crank seal, four-bolt mains, cast pistons, and a hydraulic flat tappet cam with a very mild 194/202 duration.
For 1973 to 1987 trucks, Chevrolet Performance offers this E-Rod LC9 with performance-enhancing cam phasing as an LS retrofit.
Rated at 250 hp and 350 lb-ft of torque (at 3,600 rpm), this engine is not a powerhouse, but as a stock replacement engine that’s all brand new (not rebuilt), it dwarfs the power output of the small-blocks that came from the factory in these trucks. Pace also has a version that makes 300 hp and 356 lb-ft.
Pace Performance: GM HT383 Crate Engine, part no. 12499101. Torquey engines are what this story is all about, and Pace’s version of the GM HT383 makes a peak of 425 lb-ft of torque at 3,500 rpm and over 400 lb-ft between 2,500 and 4,000 rpm, which is perfect for an off-road engine.
In fact, Pace’s Fitch told us, “This engine is specially tuned for torque and great power for trucks in a small-block package. With its 3.80-inch stroke [crank] and Vortec cylinder heads, the HT 383 makes awesome torque down low where you need it for towing or four wheeling.
A complete re-design was done for the fourth-gen (1988 to 1998) GM C/K trucks, along with a new 4×4 independent front suspension.
Developed as a high-torque engine with a low-end torque-grind roller cam, heavy duty forged powdered metal connecting rods, forged crankshaft, and hypereutectic pistons, the HT 383 is designed for hard work. Its 325 hp output at 4,500 rpm doesn’t hurt either,” continued Fitch. The HT 383 should only be used in 1979 and earlier pre-emissions street vehicles or any year off-road only vehicles.
For the latest in affordable power, durability, and fuel economy, take a look at the LS Connect and Cruise packages. – Chuck Fitch.
Chevrolet Performance: E-Rod LC9, part no. 19258004. Dr. Jamie Meyer at Chevrolet Performance calls this “an affordable LS crate engine with power and durability.” It’s based on the same engine used in hundreds of thousands of GM trucks, including the Silverado and Suburban, and is a better way to go than pulling one out of a wrecked truck in the junkyard.
You can get this engine two ways: a conventional 5.3L assembly (shown here), or the E-Rod version that also includes performance-enhancing camshaft phasing. Because it’s an E-Rod, it comes with the controller and other hardware to keep the smog cops at bay, if that’s a concern. It makes 326 hp at 5,400 rpm and over 300 lb-ft of torque from 2,000 to 4,800 rpm, and has an aluminum block and heads, so it’s lighter than the engine you’re replacing.
While not complete drop-in crate motors, SDPC has direct replacement long blocks for the 1988 to 1998 GM C/K trucks.
1988-1998 CHEVY/GMC GMT400 TRUCKS
General Motors went through a massive redesign on its light trucks for the 1988 model year with much sleeker sheet metal, more cab options, and a brand-new 4×4 independent front suspension.
Engine choices started with a wimpy 4.3L V6 and went up to a 7.4L (454 ci) big-block, with two diesel choices as well. While not a 4×4, Chevy did release the 454 SS pickup, a high-performance model with a black exterior, red interior, a good old-fashioned TH400, and steep gears.
SDPC: 350 V8 long-block, part no. 12568758 (for ‘87-’95) and 12530282 (‘86-2000). While not truly complete, drop-in crate motors, Scoggin-Dickey has replacement long-blocks specifically for this generation of trucks, and they’re all new, not rebuilt. They also come with a 36-month/100,000 mile limited warranty, which is nice.
SDPC’s Keith Wilson said, “The 0282 version comes with Vortec heads and a hydraulic roller cam that produces great low-end torque needed for pulling or climbing, and the engine needs no tuning or accessory changes.”
Chevrolet Performance has this hi-po replacement HT502 that will make your fourth-gen C/K one bad body.
Chevrolet Performance: HT502, part no. 88890534. While the LS engines are all the rage in the off-road market, it’s still hard to beat the brute torque of a big-block, and Chevy’s HT502 is a bad boy. The HT502 is rated at 377 hp and a whopping 512 lb-ft of trailer-tugging torque—way more than the factory ever offered and more than you’ll probably get with a standard rebuild. It is uniquely suited to pre-1978 trucks, but is adaptable to a variety of applications, including the GMT400 series of trucks.
SDPC: LS3 Connect & Cruze, part no. CPSLS34L65E. Wilson at SDPC said this is “the ultimate upgrade for classic trucks. It makes 430 hp and 424 lb-ft of torque with drivability that’s far better than any previous carbureted or fuel-injected small-block.” Don’t forget, since it’s an all-aluminum LS, you’ll save a lot of weight with this engine swap.
The trans that comes with this package is a 4L65E with a 3.06:1 first gear and an 0.70:1 overdrive, making it great for low-speed off-road driving and high-mileage highway cruising. SDPC also has part no. CPS3764804L70E, a similar LS3 that makes 480 hp and 475 lb-ft with a 4L70E trans. Wilson said it has, “a slightly racier idle and a significant increase in torque.”
The LS3 Connect and Cruise retrofit is recommended by SDPC for 1988 to 1998 C/K trucks as the ultimate upgrade for GM trucks of that era.
1999-2007 CHEVY/GMC GMT800 TRUCKS
General Motors officially dropped the C/K designation when they came out with the Chevy Silverado and GMC Sierra in 1999. You could get one with a Vortec 4.3L V6, and V8s in 4.8L, 5.3L, and 6.0L displacements, and as with all vehicles with GM LS engines, the trucks were making some very respectable power.
Since these trucks are still fairly new, there are not really any applicable direct replacement engines that are any different than what came in the truck originally, which in most cases is a 5.3L LS. Chevrolet Performance, Pace and SDPC certainly have replacement long-blocks, but they all say that you should call and provide your truck’s VIN to order the correct replacement part number.
The C/K designation was replaced by Silverado/Sierra nameplates for the 1999 to 2007 pickups, and this was the first generation to come with LS powerplants.
The LC9 is tuned for exceptional torque (335 lb-ft at 4,000) at low RPM, and is a great choice for off-road projects. – Keith Wilson
SDPC: LS 327/327 Base Upgrade Option, part no. 19165628. The GMT800 series trucks came with the 5.3L (327 ci) LS from the factory, and GM sold a whole bunch of them. To bump up the horsepower and torque curves, Chevrolet upgrades the production engine with a higher-torque cam and Grafel-coated high silicon pistons.
Wilson at SDPC said this engine is, “Perfect for those who want to swap all their components over to a new long-block with a hotter cam.” This engine will make 372 hp and 347 lb-ft of torque, but a new computer tune will be required.
SDPC recommends its LS 327/327 base upgrade option as a good hi-po replacement choice for the first-gen Silverado/Sierra pickups.
Because these trucks came with LS engines from the factory, it would be silly to replace it with a traditional small-block or big-block. However, there are several LS upgrade options from all three companies.
Wilson recommends the SDPC part no. 19301358 LS3/480 that makes 480 hp and 475 lb-ft of torque, saying, “This is a super easy swap for the vehicles with an LS series engine already installed.”
Fitch at Pace Performance suggested its part no. CPSLC94L70E Connect & Cruise package that makes 335 lb-ft of torque at 4,000 rpm. The kit includes a factory-engineered engine-and-transmission combination that has all the electronic control modules, wiring harnesses and other key components you need with the simplicity of one part number.
As an LS upgrade to the GMT800 trucks, SDPC suggests its LS3/480 that makes 480 hp and 475 lb-ft of torque.
Meyer from Chevrolet Performance isn’t messing around with this one, recommending the incredible LSA 6.2L engine, part no. 19260164. This is the motor out of the Cadillac CTS-V with great internals and a 1.9L supercharger. This crate engine comes fully dressed, from the top of the charge-cooled supercharger assembly to the ignition system, water pump, balancer, and more.
Meyer said, “It is a less-costly alternative to the LQ9 engine and makes a great transplant for any off-road LS-powered vehicle or pre-1976 truck.” It also comes with conventional wet-sump lubrication system, and makes a healthy 556 hp at 6,100 rpm and over 500 lb-ft of torque, but because it’s a supercharged engine designed for a car, the torque is not pool table-flat like some other engines.
2007-2013 CHEVY/GMC GMT900 TRUCKS
The all-new generation of the Silverado/Sierra, the GMT900, came out as the previous generation was still in production, hence the year model overlap. The new truck had a redesigned exterior, interior, chassis, and more power in some of the engines.
Chevrolet Performance isn’t messing around recommending its LSA 6.2L V8 crate engine as an upgrade for any LS-powered off-roader. It kicks out 500 lb-ft of torque.
Improved aerodynamics on the GMT900 trucks reaped more miles per gallon, as did the Active Fuel Management on the 5.3L and 6.0L V8s. You could also get the high-po 6.2L from the Escalade/Denali with 403 hp and 417 lb-ft of torque, and there was even a hybrid, though we wouldn’t want to do any engine swapping on the latter model.
Like the previous generation, direct replacement engines are certainly available for these trucks, but you should call and provide your VIN to get the right one.
The GMT900 series (2007 to 2013) of Silverado/Sierra trucks has a model-year overlap with the GMT800 since it came out mid-year, but offered Active Fuel Management on the 5.3L and 6.0L V8s.
SDPC: LS 327/327 Base, part no. 19165628. SDPC’s Wilson recommends the same upgraded 5.3L as for the previous generation trucks. Again, this long-block has a higher-torque cam grind and different pistons, and accepts the existing parts and accessories. It will make 327 hp and 347 lb-ft of torque.
Pace Performance: LC9 5.3L and 4L70E 4WD package, part no. CPSLC9EROD4L70E. Fitch at Pace suggests an engine from the Chevrolet Performance E-Rod lineup. It’s a new LC9 5.3L with cam phasing that alters camshaft timing to optimize performance and efficiency.
The LC9 5.3L V8 from the GM Performance E-Rod line offers torque and dependability for off-roaders, and is a great LS retrofit choice for the GMT900 trucks.
SDPC’s Wilson volunteered the same, telling us, “If you’re looking for an affordable alternative to a used LS engine for your swap project, and torque and dependability are the priority over maximum horsepower, check out the new LC9 5.3L engine from Chevrolet Performance. The LC9 is tuned for exceptional torque (335 lb-ft at 4,000) at low RPM, and is a great choice for off-road projects.”
The LC9 5.3L system features a complete GMPP controller system, aluminum engine block, intake manifold, throttle body, and fuel rails. All of the E-Rod engines include the necessary engine controller, with specific calibrations for automatic or manual transmissions.
Things To Remember
No matter which direction you choose to go, be sure to spend some time talking to the tech people at Chevrolet Performance, Pace, or SDPC about exactly what you will need to make the swap work. Having all the right parts in the first place will save you hours of work, handfuls of cash, and keep you out of trouble. Then you’ll have your favorite ol’ truck, with loads of new power.
With the right crate motor upgrade to that classic GM truck, you can give it an entirely new life.